Removable contact tip



R. v. H. RUSSELL 2,008,927

REMOVABLE CONTACT TIP July 23, 1935.

'Filed June 1'7, 1931 INVENTOR WKA M ATTORNEY 8 controllers.

Patented July 23, 1935 REMOVABLE CONTACT TIP Roslyn V. H. Russell, Niagara Falls,'N. Y. Application June 17, 1931, Serial No. 545,049

10 Claims.

The present invention relates to contact tips and more particularly to removable contact tips adapted to be attached to the type of contact finger used in connection with the drum type An example of such finger is disclosed. in my co-pending application, Serial No. 530,175, filed April 15 1931.

An object-of my invention is to provide a tip which may be removed from the contact finger, or reversed, with the minimum of effort.

A further object of my invention is to provide ac'ontact tip which is simple in construction and which can be manufactured at a minimum cost.

A further object of my invention is to provide a contact tip which is positively held against rotational movement with respect to the finger to which it is secured.

Other objects, features and advantages will appear as the description proceeds:

In the drawing wherein I have illustrated one formof my invention,

Figure 1 is aycross sectional view thereof.

Figure 2 is a cross-sectional View of the copper tip member.

Figure 3 is a perspective view of said tip member.

Figure 4 is a detailed view of the bolt which is employed for-securingthe tip in position.

Figure 5 is a detailed View of the special form of locating washer, and 7 Figures 6 and Tare plan and sectional views respectively of a modificationr Referring to the drawing, reference numeral HI designates a contact tip preferably of harddrawn copper, which is secured to the supporting member *I i of the contact finger. Between membersylll and i I is a laminated copper strip .12 which serves as a current conductor. The tip 'IOvis secured to the supporting member H by means of a bolt 13, preferably of hardened steel,

having a head M and a nut I5. A lock-washer l 5-a is employed to prevent nut"! 5 from becoming loosened. The manner in which the tip in is secured to the bolt I3 constitutes an essential feature of my invention. Looking at Figures 2 and 3, it will be noted that the tip It is provided in the central portion of the uppersurtace thereof with a recess is. Bolt head I4 is provided with a lower portion l1 and an upper :portion 18 and between said portions there extends an annular groove IS. The lower end of portion I is beveled as indicated at 11-05. The .tliai'neter of said portion is equal to or very slight- :ly greater than the diameter of recess 16. The diameter of portion l 8 is sufficiently greater than that of recess l6 so that it overhangs the edge of said recess. Portion I8 is preferably hexagonal in cross-section to prevent rotational movement thereof after same has been secured in position on the recess 16. l I

In securing the tip ID to the bolt head M, the 5 latter is placed in a punch press and the tip [0 is placed in an anvil having a recess into which said tip fits in such a manner that recess 16, is in registry with the bolt l3. As the punch press is moved downwardly, theportion. ll of the bolt head will enter recessIIB and be moved downwardly therein, the periphery of said" portion being in tight frictional engagement with the wall of said recess. The under surface of top portion 18 will engage with the portion of the 15 tip immediately surrounding recess I6. '-1" urther downward movement of the bolt I 3 will cause the metal, which is overhung by portion I 8 to be forced downwardly into the annular recess i9 and at the same time, the lower portion H 20 of the bolt head l4 will be firmly embedded in the lower portion of the recess I6. I have found that in a tip constructed in the manner described, the metal which is forced into the annular recess i9 positively locks the bolt in position and pre- 25 vents'removal of the same f-rom the tip.

In order to prevent rotational movement of the tip about the finger H, I have provided the tip at its upper surface with a pair of transverse slots 20. Located on the bolt l3, between the nut l5 and the supporting member I l, is a washer 2| of the type illustrated in Figure 5. It will be noted that the washer is provided with a pair of depending side flanges 22 and a front flange '23 which is slightly longer than the side flanges 22. The lower edge of flange 23 is adapted to fit in one of the groooves 20 and thus prevent rotational movement of the tip. The construction is given further rigidity by flanges 22 which extend downwardly'in contact with the edges of members II and I2. f p

'In Figures 6 and 7 I have shown a modification in which, instead of a groove 20, a pair of short grooves 24' are provided adjacent 'either end of the tip. The forward end of the supporting member l'I-a is bifurcated and the two protruding bifurcations are bent downwardly to fit within said short grooves 24 and thus prevent rotational movement of said tip, d P

In the assembly of tip 10 with bolt -l3 'the latter 'is placed in aninvertedposition in the anvil. It willbe obvious from the above that as the punch press descends, it will force portion H of bolt head I 4 into recess Sand in tight engagement PATENT orricg with the wall thereof. In fact, as the bolt is preferably made of steel and the tip is of copper, the action of the punch press on said bolt results in its being entirely embedded in the softer metal. Bevel I'I-a permits of more easy passage of the bolt head into the recess It. The portion I8 of said bolt head, however, being of greater diameter than said recess I6, will engage the metal constituting the upper edge thereof and carry it downwardly under the pressure of the ram. As said metal is relatively soft, it will flow into groove I9 and, as above pointed out, constitute a means for positively locking the bolt in position in the tip.

From the above it will be seen that I have provided a tip which is extremely simple to manufacture and which is rigidly held in operating position. When the tip becomes slightly worn on the one side, it may be reversed merely by loosening the nut I5 sufiiciently to permit the lower edge of flange 23, or of the bifurcated portions of member II-a, as the case may be, to clear the upper edge of the slots provided to receive them,

when the tip may be turned at will. To remove the tip it is only necessary to remove the nut I5 from bolt I3.

The washer 2|, co-operating with the slot 20, absolutely prevents rotational movement of the tip III with respect to the finger II. The side flanges 22 of the washer, prevent the latter from rotational movement during the tightening of the nut I5. It will thus be seen that I have provided an extremely simple arrangement whereby the position of the tip I with respect to the finger I I cannot be varied from that desired.

An important advantage of my invention is that when the nut I is turned to tighten the tip in position, there is no tendency to pull the bolthead I4 from its embedded position in the tip III, dueto the fact that the upper surface of portion I8 of the bolt-head bears directly against the under surface'of the conductor I2. As the nut is turned, the conductor I2, supporting member II and washers I5--e and 20 are compressed between the nut and said portion I8 of the bolthead. Obviously, if the portion I8 were omitted, the tendency upon the tightening of the nut I5 would be to pull the bolt-head I4 from its position as shown in Figures 1 and '7, which would result in loosening of the bolt-head from the tip III to permit rotational'movement of the tip ID relative to the bolt.

In the drawing I have illustrated one form of my invention. Many modifications will occur to those skilled in the art. I intend this patent to cover all such modifications that come within the scope of the appended claims.

What I claim as new and desire to protect by Letters Patent is 1. A contact tip comprising an integral piece of metal in combination with securing means embedded therein, said securing means having spaced horizontally extending portions with a recess therebetween embedded in said contact tip, a portion of said tip being interposed between said spaced portions whereby said securing means is positively held in position in said tip.

2. A contact finger comprising a supporting member, a contact tip adapted to be supported thereby, a member-embedded in said contacttip forsecuring said contact tip to said supporting member, and means adapted to fitv over a portion 'of said supporting member and to interlock with said contact tip to prevent rotational movement of said contact tip with respect to said supporting member.

3. In a contact finger, a supporting member, a contact tip having a recessed face for engaging the supporting member, and means rigid with the supporting member and engaging the recess in the contact tip for positively preventing rotational movement of said contact tip with respect to said supporting member and linear movement longitudinally or laterally of .said supporting member. v

4. In a contact finger tip, a supporting member, a contact tip having a recess formed therein, means for securing said contact tip to said supporting member, and means adapted to engage a portion of said supporting member and the walls of said recess to prevent rotational movement of said contact tip with respect to said supporting member.

5. In a contact finger, a supporting member having an aperture, a contact tip having a recess formed therein adapted to be supported by said supporting member, a bolt having its head embedded in said contact tip adapted to extend through said aperture to hold said contact tip in position, and a washer having a pair of side flanges adapted to engage said supporting member, and an end flange adapted to enter said contact-tip recess for positively preventing rotational movement of said contact tip with respect to said supporting member.

6. A contact tip in combination with securing means comprising a shank for engagement with a supporting member and a head embedded in the tip, said head comprising spaced apart upper and lower portions forming a recess therebetween, said upper portion being of greater area than the lower portion and a part of the tip being interposed in the recess between the upper and lower portions caused by the deformation of the tip by the upper portion when the securing means is longitudinally forced into the tip.

'7. A contact tip comprising an integral piece of metal in combination with securing means embedded therein, said securing means having spaced annular flanges with a recess therebetween embedded in said contact tip, one of said flanges being unround to prevent rotation of the securing means with respect to the tip, and a portion of said tip being interposed in the recess ber tween said spaced portions whereby said securing means is held against longitudinal movement in said tip.

8. A contact tip comprising an integral piece of metal in combination with securing means embedded therein, said securing means having spaced horizontally extending portions and a recess therebetween embedded in said contact tip, with a portion of said tip interposed in said recess, the upper surface of one of the spaced horizontally extending portions being flush with the top surface of the tip and forming a continuous surface therewith, whereby the stresses incident to the securing of said tip to said supporting member are prevented from being transmitted to the embedded portion of said securing means.

9. In a contact finger, a contact tip, a supporting member therefonsaid contact tip being recessed on its surface engaged by the supporting member, and a washer adapted to fit over a portion of said supporting member and having side flanges for engaging the sides of the supporting member, said washer also having a front flange adapted to fit over the front end of the supporting member and engage the recess in the tip for holding the tip from movement with respect to the supporting member.

10. In a contact finger, a, Supporting member 5 having extending lugs angularly disposed with respect to the plane of the member, a contact tip having a flat surface for engagement with the supporting member and recessed for engagement by the lugs on the supporting member, and securing means for holding the tip in position on the supporting member, whereby the tip is positively prevented from rotary or longitudinal movement with 

